Aluminium crystallises in a cubic close packed structure. Is metallic radius is 125 pm. (i) What is the length of the side of the unit cell ? (ii) How many unit cells are there in 1-00 cm^3 of aluminium ?

Aluminium crystallises in a cubic close packed structure. Is metallic

1.	Aluminium crystallises in a cubic close packed structure. Is metallic radius is 125 pm. (i) What is the length of the side of the unit cell ? (ii) How many unit cells are there in 1-00 cm^3 of aluminium ?
Answer» SOLUTION :(i)ccp=fcc. For fcc, `a=2sqrt2r`= 2 X 4.414 x 125 pm =354pm (ii)Volume of one unit cell =`(354xx10^(-10)cm)^3=4.44xx10^(-23) cm^3` Unit CELLS in `1 cm^3 =1/(4.44xx10^(-23))=2.25xx10^22`